Semiconductor Wafer and Method of Manufacturing Semiconductor Devices in a Semiconductor Wafer

ABSTRACT

A method of manufacturing semiconductor devices in a semiconductor wafer comprises forming charge compensation device structures in the semiconductor wafer. An electric characteristic related to the charge compensation device structures is measured. At least one of proton irradiation and annealing parameters are adjusted based on the measured electric characteristic. The semiconductor wafer is irradiated with protons and annealed based on the at least one of the adjusted proton irradiation and annealing parameters. Laser beam irradiation parameters are adjusted with respect to different positions on the semiconductor wafer based on the measured electric characteristic. The semiconductor wafer is irradiated with a photon beam at the different positions on the wafer based on the photon beam irradiation parameters.

BACKGROUND

Semiconductor devices known as charge compensation or super junction(SJ) semiconductor devices, for example SJ insulated gate field effecttransistors (SJ IGFETs) are based on mutual space charge compensation ofn- and p-doped regions in a semiconductor substrate allowing for animproved trade-off between area-specific on-state resistance Ron x A andbreakdown voltage Vbr between load terminals such as source and drain.Performance of charge compensation of SJ semiconductor devices dependson a lateral or horizontal charge balance between the n-doped andp-doped regions. Process tolerances lead to deviations of a targetcharge balance, i.e. to a de-tuning of a desired degree of chargebalance that may result in an undesirable decrease of device performancesuch as a reduction in a source to drain breakdown voltage.

It is desirable to improve the trade-off between the area-specificon-state resistance and the blocking voltage of a super junctionsemiconductor device and to reduce the impact of process tolerances onthis trade-off.

SUMMARY

An embodiment refers to a method of manufacturing semiconductor devicesin a semiconductor wafer. The method comprises forming chargecompensation device structures in the semiconductor wafer. An electriccharacteristic related to the charge compensation device structures ismeasured. At least one of proton irradiation and annealing parametersare adjusted based on the measured electric characteristic. Thesemiconductor wafer is irradiated with protons and annealed based on theat least one of the adjusted proton irradiation and annealingparameters. Photon beam irradiation parameters are adjusted with respectto different positions on the semiconductor wafer based on the measuredelectric characteristic. The semiconductor wafer is annealed with aphoton beam at the different positions on the wafer based on the photonbeam irradiation parameters.

According to another embodiment of a semiconductor wafer, thesemiconductor wafer comprises a plurality of semiconductor dies. Each ofthe plurality of semiconductor dies comprises a charge compensationstructure including p-doped and n-doped regions arranged consecutivelyin a semiconductor substrate along a lateral direction. A first dopantspecies dominates a doping profile of the p-doped regions. A seconddopant species dominates a doping profile of the n-doped regions. Eachof the plurality of semiconductor dies further compriseshydrogen-related donors in the p-doped and n-doped regions. Thehydrogen-correlated donors differ from the second dopant species. Amaximum concentration of the hydrogen-related donors in the p-dopedregions of a first die of the plurality of semiconductor dies is morethan 5% greater than a maximum concentration of the hydrogen-relateddonors in the p-doped regions of a second die of the plurality ofsemiconductor dies.

Those skilled in the art will recognize additional features andadvantages upon reading the following detailed description and onviewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification. The drawings illustrate the embodiments ofthe present disclosure and together with the description serve toexplain principles of the disclosure. Other embodiments and intendedadvantages will be readily appreciated as they become better understoodby reference to the following detailed description.

FIGS. 1A to 1F are schematic views illustrating one embodiment of asemiconductor wafer with respect to different process features.

FIG. 2 is a schematic diagram illustrating one example of a profile ofhydrogen-related donors generated by irradiating a semiconductor wafer,for example the semiconductor wafer illustrated in FIG. 1A with protonsfollowed by an annealing process and a photon irradiation process.

FIG. 3 is a schematic diagram illustrating another example of a profileof hydrogen-related donors generated by irradiating a semiconductorwafer, for example the semiconductor wafer illustrated in FIG. 1Amultiple times with protons followed by an annealing process and photonirradiation process.

FIG. 4A is a schematic diagram illustrating embodiments of n-type dopantprofiles including hydrogen-related donors along line B-B′ of thesemiconductor wafer illustrated in FIG. 1B with respect to differentdies of the semiconductor wafer.

FIG. 4B is a schematic diagram illustrating embodiments of n-type andp-type dopant profiles including hydrogen-related donors along line C-C′of the semiconductor wafer illustrated in FIG. 1B with respect todifferent dies of the semiconductor wafer.

FIG. 4C is a schematic diagram illustrating embodiments of n-type dopantprofiles including hydrogen-related donors along line D-D′ of thesemiconductor substrate illustrated in FIG. 1B with respect to one ofthe dies of the semiconductor wafer.

FIG. 5 is a schematic cross-sectional view of one embodiment of alateral semiconductor device with a charge compensation structureincluding hydrogen-related donors in both of alternating p- and n-typeregions of the charge compensation structure.

FIG. 6 is a schematic top view illustrating an embodiment of asemiconductor wafer including different doping profile ofhydrogen-related donors in different semiconductor dies.

FIGS. 7A to 7E are schematic cross-sectional views of super junctionsemiconductor devices including an end-of-range peak of implantedhydrogen-related donors within a compensation structure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof and in which are shownby way of illustrations specific embodiments in which the invention maybe practiced. It is to be understood that other embodiments may beutilized and structural or logical changes may be made without departingfrom the scope of the present invention. For example, featuresillustrated or described for one embodiment can be used on or inconjunction with other embodiments to yield yet a further embodiment. Itis intended that the present invention includes such modifications andvariations. The examples are described using specific language, whichshould not be construed as limiting the scope of the appending claims.The drawings are not scaled and are for illustrative purposes only. Forclarity, the same elements have been designated by correspondingreferences in the different drawings if not stated otherwise.

The terms “having”, “containing”, “including”, “comprising” and the likeare open and the terms indicate the presence of stated structures,elements or features but not preclude the presence of additionalelements or features. The articles “a”, “an” and “the” are intended toinclude the plural as well as the singular, unless the context clearlyindicates otherwise.

The term “electrically connected” describes a permanent low-ohmicconnection between electrically connected elements, for example a directcontact between the concerned elements or a low-ohmic connection via ametal and/or highly doped semiconductor. The term “electrically coupled”includes that one or more intervening element(s) adapted for signaltransmission may exist between the electrically coupled elements, forexample elements that temporarily provide a low-ohmic connection in afirst state and a high-ohmic electric decoupling in a second state.

The Figures illustrate relative doping concentrations by indicating “−”or “+” next to the doping type “n” or “p”. For example, “n-” means adoping concentration that is lower than the doping concentration of an“n”-doping region while an “n+”-doping region has a higher dopingconcentration than an “n”-doping region. Doping regions of the samerelative doping concentration do not necessarily have the same absolutedoping concentration. For example, two different “n”-doping regions mayhave the same or different absolute doping concentrations.

The terms “wafer”, “substrate”, “semiconductor body” or “semiconductorsubstrate” used in the following description may include anysemiconductor-based structure that has a semiconductor surface. Waferand structure are to be understood to include silicon (Si),silicon-on-insulator (SOI), silicon-on sapphire (SOS), doped and undopedsemiconductors, epitaxial layers of silicon supported by a basesemiconductor foundation, and other semiconductor structures. Thesemiconductor need not be silicon-based. The semiconductor could as wellbe silicon germanium (SiGe), germanium (Ge) or gallium arsenide (GaAs).According to other embodiments, silicon carbide (SiC) or gallium nitride(GaN) may form the semiconductor substrate material.

The term “horizontal” as used in this specification intends to describean orientation substantially parallel to a first or main surface of asemiconductor substrate or body. This can be for instance the surface ofa wafer or a die.

The term “vertical” as used in this specification intends to describe anorientation which is substantially arranged perpendicular to the firstsurface, i.e. parallel to the normal direction of the first surface ofthe semiconductor substrate or body.

In this specification, a second surface of a semiconductor substrate orsemiconductor body is considered to be formed by the lower or backsidesurface while the first surface is considered to be formed by the upper,front or main surface of the semiconductor substrate. The terms “above”and “below” as used in this specification therefore describe a relativelocation of a structural feature to another

In this specification, n-doped is referred to as first conductivity typewhile p-doped is referred to as second conductivity type. Alternatively,the semiconductor devices can be formed with opposite doping relationsso that the first conductivity type can be p-doped and the secondconductivity type can be n-doped.

Processing of a semiconductor wafer may result in semiconductor deviceshaving terminal contacts such as contact pads (or electrodes) whichallow electrical contact to be made with the integrated circuits ordiscrete semiconductor devices included in the semiconductor body. Theelectrodes may include one or more electrode metal layers which areapplied to the semiconductor material of the semiconductor chips. Theelectrode metal layers may be manufactured with any desired geometricshape and any desired material composition. The electrode metal layersmay, for example, be in the form of a layer covering an area. Anydesired metal, for example Cu, Ni, Sn, Au, Ag, Pt, Pd, and an alloy ofone or more of these metals may be used as the material. The electrodemetal layer(s) need not be homogenous or manufactured from just onematerial, that is to say various compositions and concentrations of thematerials contained in the electrode metal layer(s) are possible. As anexample, the electrode layers may be dimensioned large enough to bebonded with a wire.

In embodiments disclosed herein one or more conductive layers, inparticular electrically conductive layers, are applied. It should beappreciated that any such terms as “formed” or “applied” are meant tocover literally all kinds and techniques of applying layers. Inparticular, they are meant to cover techniques in which layers areapplied at once as a whole like, for example, laminating techniques aswell as techniques in which layers are deposited in a sequential mannerlike, for example, sputtering, plating, molding, CVD (Chemical VaporDeposition), physical vapor deposition (PVD), evaporation, hybridphysical-chemical vapor deposition (HPCVD), etc.

The applied conductive layer may comprise, inter alia, one or more of alayer of metal such as Cu or Sn or an alloy thereof, a layer of aconductive paste and a layer of a bond material. The layer of a metalmay be a homogeneous layer. The conductive paste may include metalparticles distributed in a vaporizable or curable polymer material,wherein the paste may be fluid, viscous or waxy. The bond material maybe applied to electrically and mechanically connect the semiconductorchip, e.g., to a carrier or, e.g., to a contact clip. A soft soldermaterial or, in particular, a solder material capable of formingdiffusion solder bonds may be used, for example solder materialcomprising one or more of Sn, SnAg, SnAu, SnCu, In, InAg, InCu and InAu.

A dicing process may be used to divide the semiconductor wafer intoindividual chips. Any technique for dicing may be applied, e.g., bladedicing (sawing), laser dicing, etching, etc. The semiconductor body, forexample a semiconductor wafer may be diced by applying the semiconductorwafer on a tape, in particular a dicing tape, apply the dicing pattern,in particular a rectangular pattern, to the semiconductor wafer, e.g.,according to one or more of the above mentioned techniques, and pull thetape, e.g., along four orthogonal directions in the plane of the tape.By pulling the tape, the semiconductor wafer gets divided into aplurality of semiconductor dies (chips).

FIGS. 1A to 1E refer to an embodiment of manufacturing semiconductordevices in a semiconductor wafer.

The method comprises forming charge compensation device structures in asemiconductor wafer 105. In the schematic top view of FIG. 1A, a portionof the semiconductor wafer 105 is illustrated. The semiconductor wafer105 may include a plurality of semiconductor dies 107. Each one of thesemiconductor dies 107 may include one of the charge compensation devicestructures. An area 108 between the semiconductor dies 107 may be usedfor wafer dicing after completion of wafer processing. Test structuresfor monitoring process stability may be arranged in the area 108. Thetest structures may include pn junctions between several or anycombination of p-doped regions and n-doped regions. In additional or asan alternative, the test structures may also include resistors formonitoring sheet resistance of the p-doped regions and the n-dopedregions. When arranging the test structures in the area 108, measurementof the test structures may be carried out before dicing thesemiconductor wafer 105 into singularized semiconductor dies 107.

FIG. 1B illustrates one embodiment of a cross-sectional view along lineA-A′ of the semiconductor die 107 illustrated in FIG. 1A. Thesemiconductor die 107 includes a charge compensation device structureincluding alternating n-doped and p-doped regions 111, 112 alternatingalong a lateral direction x. According to an embodiment, the n-dopedregions 111 and the p-doped regions 112 extend in parallel as stripesalong a lateral direction perpendicular to the drawing plane of FIG. 1B.According to another embodiment, the p-doped regions 112 constituteseparate p-doped pillars or islands surrounded by the n-doped region 111being a continuous n-doped region with respect to a top view of FIG. 1B.According to another embodiment, the n-doped regions 111 are separaten-doped pillars or islands surrounded by the p-doped region 112 being acontinuous p-doped region with respect to a top view of FIG. 1B. A topview of the p-doped islands or n-doped islands may be square-shaped,rectangular, circular or polygonal, for example. The charge compensationdevice structure may be formed by super junction process technologiessuch as multiple epitaxy technology and deep trench technology. Also acombination of multiple epitaxy technology and deep trench technologymay be used to formed the charge compensation device structure.

In the embodiment illustrated in FIG. 1B, the semiconductor die 107includes a vertical super junction (SJ) n-channel field-effecttransistor (NFET). The vertical SJ NFET includes an optional n-dopedfield stop zone 114 between the charge compensation device structure andan n⁺-doped drain region 115. Each one of the p-doped regions 112adjoins a bottom side of a p-doped body region 117. The p-doped bodyregion 117 is electrically coupled to a source contact 118 at a firstside 120 of the semiconductor wafer 105 via an optional p⁺-doped bodycontact region 121. N⁺-doped source regions 122 adjoin the first side120 and are electrically coupled to the source contact 118. A gatestructure including a gate dielectric 124 and a gate electrode 125 isarranged on the semiconductor wafer 105 at the first side 120 and isconfigured to control a conductivity in a channel region 127 by fieldeffect. Thereby, a current flow between the source contact 118 at thefirst side 120 and a drain contact 126 at a second side 128 can becontrolled. The source and drain contacts 118, 126 may includeconductive materials such as metal(s) and/or highly doped semiconductormaterial(s). The source and drain contacts 118, may be present beforethe subsequent method features described with respect to FIGS. 1C to 1Ebelow. According to another embodiment, at least one of the source anddrain contacts, e.g. the source contact 118 or the drain contact 126 orboth contacts 118, 126 will be formed after the method featuresdescribed with respect to FIGS. 1C to 1E below.

The vertical SJ NFET illustrated in FIG. 1B is one example of asemiconductor device including the charge compensation device structure.Other embodiments may include vertical SJ p-channel FETs, lateral SJFETs including source and drain contacts at a common side, lateral orvertical insulated gate bipolar transistors (IGBTs), for example.

Referring to the schematic view illustrated in FIG. 1C, the methodfurther comprises measuring an electric characteristic α_(i) related tothe charge compensation device structures. The electric characteristicα_(i) may include a plurality of measurements at different waferpositions, for example. In the embodiment illustrated in FIG. 1C, thesemiconductor wafer 105 is arranged on a carrier 130, for example a XYstage and the electric characteristic a, is measured via a measurementequipment 132. The measurement equipment 132 may include a wafer prober.As an example, the semiconductor wafer 105 may be vacuum-mounted on awafer chuck and electrically connected via probes brought intoelectrical contact with the semiconductor wafer 105. When the electriccharacteristic a, related to a position of a first die has beenmeasured, the wafer prober moves the semiconductor wafer 105 so thatmeasurement of the electric characteristic of a second die can start.This procedure may be repeated until a desired mapping of measurementsacross a surface of the semiconductor wafer 105 has been achieved.According to an embodiment, the electric characteristic α_(i) includes amap of breakdown voltages Vbd between a source and a drain of a SJ FETor between a collector and an emitter of an IGBT, for example. Inaddition or as an alternative, the electric characteristic α_(i) mayfurther include a map of an output charge Qoss versus voltage, i.e. anQoss(V) characteristic. The electric characteristic may be measuredbetween respective electrodes of the SJ semiconductor device of the dieunder test or with respect to a test structure arranged within an areaof a semiconductor die 107 and/or within the area 108 illustrated inFIG. 1A. According to an embodiment, a metal electrode provides electriccontact to the test structure but any metal structures are missing in anarea of the charge compensation device structure. According to yetanother embodiment, the probes are brought into contact with highlydoped semiconductor regions of the semiconductor substrate without anyintervening metal structures. According to yet another embodiment, metalelectrodes and/or a contact support layer, e.g. a highly dopedpolysilicon layer are arranged on the semiconductor substrate forreducing a contact resistance between the probes and the semiconductorsubstrate and may be removed before proton irradiation described withrespect to FIG. 1D.

The electric characteristic α_(i) may characterize a charge balance ofthe charge compensation device structures. Since the charge balanceconstitutes a reference parameter for correction of an overall charge inthe n- and p-doped regions 111, 112, precision of correction can beimproved with respect to a correction process having the overall chargein the n- and p-doped regions 111, 112 as the reference parameter forcorrection.

Based on the electric characteristic α_(i) related to the chargecompensation device structures, proton irradiation and/or annealingparameters are adjusted. According to an embodiment, at least one ofnumber, dose and energy of proton irradiation are adjusted based on themeasured value of the electric characteristic α_(i). According to anembodiment, the adjusted proton irradiation parameters include animplantation dose in a range of 1×10¹³ cm⁻² and 3×10¹⁵ cm⁻², or 5×10¹³cm⁻² and 1×10¹⁵ cm ⁻², or 2×10¹⁴ cm⁻² and 8×10¹⁴ cm⁻² and animplantation energy in a range of 1.0 MeV and 3.0 MeV. According to anembodiment, the adjusted proton irradiation parameters are configured toshift a charge balance of the charge compensation device structure basedon the measured value of the electric characteristic towards or to atarget charge balance of the charge compensation device structure.Irradiation of the semiconductor substrate with the adjusted protonirradiation parameters will generate hydrogen-related donors leading toan increase of n-doping in both the n- and p-doped regions 111, 112 ofthe charge compensation device structure.

Referring to the schematic view of FIG. 1D, the method further comprisesirradiating the semiconductor wafer 105 with protons based on theadjusted proton irradiation parameters (c.f. I²(α_(i)) in FIG. 1D).According to an embodiment, the semiconductor wafer 105 is irradiatedfrom the first side, e.g. a front side of the semiconductor wafer 105.At the first side 120 control electrode(s) such as gate electrode(s) maybe arranged and electrically coupled to a wiring area. According toanother embodiment, the semiconductor wafer 105 is irradiated withprotons from the second side 128 opposite to the first side 120. At thesecond side 128, a drain electrode of a SJ FET or a collector electrodeof an IGBT may be arranged. According to yet another embodiment, thesemiconductor wafer 105 is irradiated with protons from the first andsecond sides 120, 128.

Referring to the schematic view of FIG. 1E, the method further comprisesannealing the semiconductor wafer 105.

According to an embodiment, annealing is carried out under inertatmosphere or air in an annealing equipment 135 such as a chamber or anoven. Annealing temperatures typically range between 350° C. and 550°C., or between 380° C. and 500° C. Duration of the annealing typicallyranges between 30 minutes and 10 hours, e.g. between 1 and 5 hours. Aresulting donor concentration and vertical distribution can also beadjusted by annealing temperature and annealing duration.

The doping is effected predominantly in the so-called end-of-rangeregion of the proton implantation, and to a lesser extent in the regionradiated through. Annealing of the semiconductor wafer 105 leads todiffusion of the hydrogen into the irradiated area and may also reachthe surface radiated through whereby the formation of complexescomprising the hydrogen atoms and the irradiation-induced defects likee.g. vacancies results in the creation of donors, e.g. so-calledhydrogen-related donors in this region.

Since at least one of the proton irradiation and annealing parametersare based on the measured electric characteristic α_(i) related to thecharge compensation devices, a precise correction process of chargebalance in the n-doped and p-doped regions 111, 112 of the chargecompensation device structure can be carried out with respect to anoverall depth of a voltage absorbing volume of the charge compensationdevice structure, e.g. with respect to an overall depth of a drift zoneof the charge compensation device. According to an embodiment, thehydrogen-related donors extend over at least 30% of a vertical extensionof a drift zone between a first side and a second side of thesemiconductor wafer 105.

According to another embodiment, a concentration of the hydrogen-relateddonors is in a range of 1×10¹³ cm⁻³ and 1×10¹⁵ cm⁻³, or 5×10¹³ cm⁻³ and8×10¹⁴ cm⁻³.

As is indicated by a dashed line 141 between FIGS. 1E and 1C, theabove-described correction process may be repeated. According to anembodiment, the electric characteristic α_(i) is measured again asdescribed with respect to FIG. 1C and, depending upon whether themeasured electric characteristic α_(i) is out of a range of tolerance,proton irradiation and annealing as illustrated in FIGS. 1D and 1E maybe carried out to increase the number of n-charges in the charge balanceof the charge compensation device structure. In case the measured valueof the electric characteristic α_(i) reveals an excess of n-type chargeswith respect to a target charge balance in the charge compensationdevice structure, proton irradiation as illustrated in FIG. 1D may bedispensed with and the number of n-type charges in the chargecompensation device structure may be lowered by an additional process ofannealing the semiconductor wafer 105 as is illustrated in FIG. 1E.Thus, depending upon whether n-type charges or p-type charges dominatethe charge balance of the charge compensation device structure, thecorrection process towards a target charge balance may either dispensewith additional proton implantation and decrease the number of n-typecharges in the charge compensation device structure by an additionalannealing process of the semiconductor substrate (c.f. FIG. 1E) or, in acase of excess p-type charges in charge compensation device structure,the number of n-type charges may be increased by additional protonimplantation and annealing as illustrated in FIG. 1D, 1E and asdescribed above. Furthermore, according to an embodiment, annealing thesemiconductor substrate may be carried out with a thermal budgetconfigured to deactivate at least a part of donors generated by protonirradiation and annealing, for example by breakup of electrically activehydrogen-vacancy complexes. Thereby, a concentration of hydrogen-relateddonors generated by proton irradiation and annealing may also bedecreased.

Based on the electric characteristic α_(i) related to the chargecompensation device structures, photon beam irradiation parameters withrespect to different positions on the semiconductor wafer are adjusted.Local heating of the semiconductor wafer 105, and hence an extent ofdecrease of hydrogen-related donor concentration depends on thermalenergy input into the semiconductor wafer 105 by absorption of thephoton beam irradiation. As a photon beam irradiation source, anyirradiation source may be used that is configured to emit radiation insuch a way that absorption of the irradiation in the semiconductor waferleads to a desired local heating. Some embodiments are based on laserbeam irradiation. Some other embodiments are based on light emittingdiode (LED) irradiation. Some other embodiments are based on light fromultraviolet (UV), infrared (IR) microwave, or visible light sources suchas lamps. Beam focusing optical elements may be used to further adjustenergy absorption or local heating in the semiconductor wafer. Thethermal energy input into the semiconductor wafer 105 may vary acrossthe surface of the semiconductor wafer 105 depending on the photon beamirradiation parameters, for example photon beam pulse length, photonbeam pulse energy, number of photon beam pulses, time between photonbeam pulses, wavelength of photon irradiation, photon beam optics,photon beam intensity. In some embodiments, pulse lengths are in a rangeof 10 ms to 400 ms, for example such that an energy deposition length inthe range of one or several micrometers may be achieved. In some otherembodiments, pulse lengths are chosen larger than 400 ms and alsounpulsed photon irradiation may be used.

Referring to the schematic view of FIG. 1F, the semiconductor wafer 105is irradiated with a photon beam 137 at the different positions on thesemiconductor wafer 105 based on the photon beam irradiation parameters.Positioning the semiconductor wafer 105 at the different positions maybe carried out by mounting the semiconductor wafer 105 on a XY stage 131and moving the semiconductor wafer by the XY stage 131 with an X-driveand a Y-drive along an XY plane, for example. Laser beam irradiation maybe carried out through a first surface of the semiconductor wafer 105,for example through a front side surface of the semiconductor wafer 105where control structures such as gate structures are formed, or througha rear side surface where load terminal contacts such as a drain contactof an insulated gate field effect transistor or a collector contact ofan insulated gate bipolar transistor are formed. In some otherembodiments, irradiation of the semiconductor wafer 105 with the photonbeam 137 is carried out through the front side surface and through therear side surface starting with irradiation through the front sidesurface followed by irradiation through the rear side surface, orstarting with irradiation through the rear side surface followed byirradiation through the front side surface. Between front- and rear sideirradiation, the semiconductor wafer 105 may be turned on the XY stage131. The XY stage 131 or another carrier for the semiconductor wafer maybe pre-heated to a temperature below a temperature of breakup orelectrical deactivation of electrically active hydrogen-vacancycomplexes, i.e. electrical deactivation of hydrogen-related donors. Inthis case, the thermal budget to be introduced into the semiconductorwafer 105 for locally breaking up electrically active hydrogen-vacancycomplexes is smaller than in the case where irradiation of thesemiconductor wafer 105 is carried out in an ambient at roomtemperature. Pre-heating is beneficial with regard to achieving ahomogeneous temperature distribution into a depth of the semiconductorwafer. In some embodiments pre-heating is carried out in a temperaturerange between 50° C. and 450° C., or between 100° C. and 350° C.

Since process tolerances lead to deviations of a target charge balanceof a super-junction semiconductor device not only from wafer to waferbut also along a wafer, i.e. to a de-tuning of a desired degree ofcharge balance that may result in an undesirable decrease of deviceperformance such as a reduction in a source to drain breakdown voltage,the above method allows for a correction or tuning of the charge balanceof a super-junction semiconductor device over a surface of thesemiconductor wafer 105 by varying irradiation parameters of localirradiation of the semiconductor wafer 105 along the lateral waferdirection, thereby varying a thermal budget introduced into thesemiconductor wafer 105, and thus a degree of deactivation ofelectrically active hydrogen-vacancy complexes.

FIG. 2 illustrates a measured profile of concentration c₁ ofhydrogen-related donors versus a depth d of a semiconductor wafer.Proton irradiation occurred from a first side, e.g. along a direction ofincreasing values of depth d which may correspond to the direction yillustrated in FIG. 1B, for example. Diffusion of the hydrogen and theformation of donors due to creation of hydrogen/vacancy-complexes in anend-of-range area 151 by thermal processing leads to an almosthomogeneous doping with hydrogen-related donors in an area 152. Byappropriately adjusting parameters such as proton irradiation dose,proton irradiation energy, annealing temperature and annealing duration,the end-of-range area 151 may be adjusted to fall within a field stopzone or a highly doped substrate portion of a charge compensation deviceand the area 152 of almost homogeneous doping with hydrogen-relateddonors may be adjusted to fall within a voltage absorbing region, forexample a drift zone of a charge compensation device structure of acharge compensation device.

FIG. 3 illustrates a measured profile of concentration c₂ ofhydrogen-related donors versus a depth d of a semiconductor wafer.Multiple proton irradiations occurred from the first side, e.g. along adirection of increasing values of depth d which may correspond to thedirection y illustrated in FIG.

1B, for example. Diffusion of the hydrogen and the formation of donorsdue to the creation of hydrogen/vacancy-complexes in and between the endof range areas by thermal processing leads to overlapping profiles ofhydrogen-related donors, whereas each one of peak areas 1530, 1531,1532, 1533 is associated with a separate proton implantation process.The sequence of proton implantations illustrated in FIG. 3 with respectto the peak areas is e.g. 1530, 1531, 1532, 1533. A broadening of theprofile in the peak area 1530 is larger than in the peak areas 1531,1532, 1533. Likewise, a broadening of the profile in the peak area 1531is larger than in the peak areas 1532, 1533 and a broadening of theprofile in the peak area 1532 is larger than in the peak areas 1533 dueto larger irradiation energies resulting in an increased width of theend-of-range peak.

By appropriately adjusting parameters such as proton irradiation dose,proton irradiation energy, annealing temperature and annealing duration,the peak areas 1530, 1531, 1532, 1533 may be adjusted with respect topeak height, broadening, depth of peak, overlap with neighboring peakareas, for example. By irradiating the semiconductor wafer with a photonbeam at different positions on the semiconductor wafer based on photonbeam irradiation parameters that may vary across the surface of thesemiconductor wafer, adjustment of the peak areas 1530, 1531, 1532, 1533with respect to peak height, broadening, depth of peak, overlap withneighboring peak areas, for example may vary across the surface of thesemiconductor wafer depending on a desired degree of charge balancecorrection.

According to other embodiments, proton irradiation may be carried outfrom opposite sides such as the first and second sides 120, 128illustrated in FIG. 1B.

FIG. 4A is a schematic diagram illustrating embodiments of n-type dopantprofiles along line B-B′ of the semiconductor wafer 105 illustrated inFIG. 1B.

The illustrated dopant profile relates to the n-doped region 111. Then-doped region 111 includes a first concentration N₁ of n-type dopants.The dopant concentration N₁ may be formed by in-situ doping whilemanufacturing the charge compensation device structure, e.g. in-situdoping during epitaxial growth or deposition. In addition or as analternative, the concentration N₁ may be formed by ion implantation ofn-type dopants, e.g. when manufacturing the charge compensation devicestructure by a so-called multiple epitaxy technology or by a deep trenchtechnology, for example. According to an embodiment, a dopant species ofthe dopant concentration N₁ may include one or more of phosphor (P),antimony (Sb) and arsenic (As). A profile of the first concentration N₁of the n-type dopants may be almost constant or include an undulationwhich may be caused by multiple ion implantation processes of n-typedopants in the multiple epitaxy technology.

In addition to the first concentration N₁ of the n-type dopants, then-doped region 111 further includes, according to an embodiment, secondconcentration profiles N₂₀₁, N₂₀₂ of hydrogen-related donors at twodifferent positions on the wafer surface. The second concentrationprofile N₂₀₁ represents a profile of hydrogen-related donors at a firstposition on the surface of the semiconductor wafer after proton andphoton beam irradiations, and the second concentration profile N₂₀₂represents a profile of hydrogen-related donors at a second position onthe surface of the semiconductor wafer after proton and photon beamirradiations. By varying the thermal budget locally introduced intosemiconductor wafer by photon beam irradiation, a correction of chargebalance may be varied across a surface of the semiconductor wafer basedon the measured electric characteristic α_(i). Although FIG. 4Aillustrates merely two different second concentration profiles havingalmost constant concentration values for illustration purposes, morethan two different second concentration profiles may be presentdepending on a number of photon beam irradiation positions and differentphoton beam irradiation parameters for local correction of the chargebalance across the wafer surface.

According to another embodiment, second concentration profiles N₂₁₁,N₂₁₂ of hydrogen-related donors may include multiple peaks due tooverlapping profiles of hydrogen-related donors caused by multipleproton irradiations at different energies and photon beam irradiationsat different positions on the wafer surface, for example. The secondconcentration profile N₂₁₁ represents a profile of hydrogen-relateddonors at a first position on the surface of the semiconductor waferafter proton and photon beam irradiations, and the second concentrationprofile N₂₁₂ represents a profile of hydrogen-related donors at a secondposition on the surface of the semiconductor wafer after proton andphoton beam'irradiations. By varying the thermal budget locallyintroduced into semiconductor wafer by photon beam irradiation, acorrection of charge balance may be varied across a surface of thesemiconductor wafer based on the measured electric characteristic α_(i).Although FIG. 4A illustrates merely two different second concentrationprofiles N₂₁₁, N₂₁₂ with multiple peaks for illustration purposes, morethan two different second concentration profiles with multiple peaks maybe present depending on a number of photon beam irradiation positionsand different photon beam irradiation parameters for local correction ofthe charge balance across the wafer surface.

FIG. 4B is a schematic diagram illustrating embodiments of p-type andn-type dopant profiles along line C-C′ of the semiconductor wafer 105illustrated in FIG. 1B. A net doping along the line C-C′ is p-type andrelates to the p-doped region 112. The p-doped region 112 includes afirst concentration P₁ of p-type dopants. The dopant concentration P₁may be due to in-situ doping while manufacturing the charge compensationdevice structure, e.g. in-situ doping during epitaxial growth ordeposition. In addition or as an alternative, the concentration P₁ maybe due to ion implantation of p-type dopants, e.g. when manufacturingthe charge compensation device structure by a so-called multiple epitaxytechnology. According to an embodiment, a dopant species of the dopantconcentration P₁ may include one or more of boron (B), indium (In),aluminum (Al), gallium (Ga). A profile of the first concentration P₁ ofp-type dopants may be almost constant or include an undulation which maybe caused by multiple ion implantation processes of p-type dopants inthe multiple epitaxy technology. In addition to the first concentrationP₁ of p-type dopants, the p-doped region 112 further includes, accordingto an embodiment, a counter-doping by the second concentration profileN₂₀₁ at a first position on the surface of the semiconductor wafer afterproton and photon beam irradiations, and a counter-doping by the secondconcentration profile N₂₀₂ at a second position on the surface of thesemiconductor wafer after proton and photon beam irradiations. Thesecond concentration profiles N₂₀₁, N₂₀₂ of hydrogen-related donors arealmost homogeneous and caused by a single proton implantation asillustrated, for example, in FIG. 2. The hydrogen-related donorsconstituting the second concentration may be simultaneously formed inthe n-doped and p-doped regions 111, 112 for the same purpose of chargebalance correction, for example.

According to another embodiment, the p-doped regions 112 further includesecond concentration profiles N₂₁₁, N₂₁₂ of hydrogen-related donors withmultiple peaks due to overlapping profiles of hydrogen-related donorscaused by multiple proton irradiations at different energies and photonbeam irradiations, for example. A second concentration profile N₂₁₁represents a profile of hydrogen-related donors at a first position onthe surface of the semiconductor wafer after proton and photon beamirradiations, and a second concentration profile N₂₁₂ represents aprofile of hydrogen-related donors at a second position on the surfaceof the semiconductor wafer after proton and photon beam irradiations. Byvarying the thermal budget locally introduced into the semiconductorwafer by photon beam irradiation, a correction of charge balance may bevaried across a surface of the semiconductor wafer based on the measuredelectric characteristic α_(i). Although FIG. 4B illustrates merely twodifferent second concentration profiles N₂₁₁, N₂₁₂ with multiple peaksfor illustration purposes, more than two different second concentrationprofiles with multiple peaks may be present depending on a number ofphoton beam irradiation positions and different photon beam irradiationparameters for local correction of the charge balance across the wafersurface.

FIG. 4C is a schematic diagram illustrating embodiments of n-type dopantprofiles along line D-D′ of the semiconductor wafer 105 illustrated inFIG. 1B. The profile along line D-D′ is an extension of the profilealong the line C-C′ into the optional n-doped field stop zone 114.

According to an embodiment, end-of-range peaks of the firstconcentrations N₂₀₁, N₂₁₁ of hydrogen-related donors are located withinthe optional n-doped field stop zone 114.

The method of charge balance correction illustrated in FIGS. 1A to 1Erelates to a vertical charge compensation device including loadterminals, e.g. source and drain at opposite first and second sides 120,128 of the semiconductor wafer 105.

The method may also be applied to other device layouts. One example ofanother device layout is a lateral charge compensation or SJ FET 500illustrated in FIG. 5. The lateral charge compensation FET 500 includesa charge compensation device structure including n-type and p-typeregions 511, 512.

The n-type and p-type regions 511, 512 constitute a voltage absorbingdrift zone arranged between an n⁺-type source region 522 and an n⁺-typedrain region 515. The n⁺-type source region 522 is arranged in a p-well517. A source electrode 518 is electrically coupled to the p-well 517via an optional p⁺-type contact region 521 and to the n⁺-type sourceregion 522. A drain electrode 527 is electrically coupled to the n⁺-typesource region 522. The n-type regions 511 are electrically coupled tothe n⁺-type drain region 515 via an optional n⁻-type drain extensionregion 545.

A planar gate structure including a gate dielectric 524 and a gateelectrode 525 is arranged on the p-well 517 between the n⁺-type sourceregion 522 and the n-type and p-type regions 511, 512. A gate electrodecontact 546 is electrically coupled to the gate electrode 525. In theillustrated embodiment of FIG. 5, the lateral charge compensation FET500 is arranged on a p-type substrate 505. Charge balance correction inthe n-type and p-type regions 511, 512 may be carried out as illustratedin FIGS. 1C to 1F and described above.

FIG. 6 is a schematic illustration of a top view of an embodiment of asemiconductor wafer 600 including a plurality of semiconductor dies, forexample semiconductor dies denoted D1, Dm, Dn. Each of the plurality ofsemiconductor dies comprises a charge compensation structure includingp-doped and n-doped regions arranged consecutively in a semiconductorsubstrate along a lateral direction. Examples of charge compensationstructures are illustrated in FIGS. 1B and 5. A first dopant speciesdominates a doping profile of the p-doped regions. A second dopantspecies dominates a doping profile of the n-doped regions. Each of theplurality of semiconductor dies further comprises hydrogen-relateddonors in the p-doped and n-doped regions. The hydrogen-correlateddonors differ from the second dopant species. Examples of dopingprofiles are illustrated in FIGS. 4A and 4B. A maximum concentrationc_(max,m) of the hydrogen-related donors in the p-doped regions of afirst die of the plurality of semiconductor dies is more than 5%greater, or more than 10% greater, or more than 30% greater, or morethan 50% greater than a maximum concentration c_(max,n) of thehydrogen-related donors in the p-doped regions of a second die of theplurality of semiconductor dies. In some embodiments, each of theplurality of semiconductor dies comprises an n-doped field stop zonebetween the charge compensation structure and a second side of thesemiconductor substrate. Within a range of the n-doped field stop zone,an end-of-range peak profile of hydrogen-related donors is smaller thana profile of another n-type dopant species of the n-doped field stopzone.

In some embodiments, the hydrogen-related donors extend over at least30% or even at least 50% or even at least 80% of a vertical extension ofa drift zone between a first side and a second side of the semiconductorsubstrate. In some embodiments, a concentration of the hydrogen-relateddonors is in a range of 1×10¹³ cm⁻³ and 5×10¹⁶ cm⁻³, or 2×10¹³ cm⁻³ and1×10¹⁶ cm⁻³, or 5×10¹³ cm⁻³ and 1×10¹⁵ cm⁻³.

An embodiment refers to a method of manufacturing a semiconductordevice. A charge compensation device structure is formed in asemiconductor substrate. An electric characteristic related to thecharge compensation device is measured. At least one of protonirradiation and annealing parameters are adjusted based on the measuredelectric characteristic. Based on the at least one of the adjustedproton irradiation and annealing parameters the semiconductor substrateis irradiated with protons, wherein an end-of-range peak of the protonsis located within the charge compensation structure, and thereafter, thesemiconductor substrate is annealed.

By positioning the end-of-range peak of the protons within the chargecompensation structure, i.e. between an upper side and a lower side ofthe charge compensation structure, a punch-through voltage of thecompensation structure may be corrected and adjusted. Thereby, thevoltage which is necessary so that a lower side part of the compensationstructure is no longer electrically floating can be adjusted aftermeasurement of the electric characteristic. In some embodiments, theelectric characteristic related to the charge compensation deviceincludes a measured characteristic of an output charge Qoss versusvoltage, i.e. an Qoss(V) characteristic. In some embodiments, theQoss(V) characteristic is measured with respect to the chargecompensation structure and/or a test structure of one or moresemiconductor dies of the semiconductor substrate. In some embodiments,the adjusted proton irradiation parameters include an implantation dosein a range of 1×10¹³ cm⁻² and 3×10¹⁵ cm⁻², or 5×10¹³ cm⁻² and 1×10¹⁵cm⁻², or 2×10¹⁴ cm⁻² and 8×10¹⁴ cm⁻² and an implantation energy in arange of 500 keV and 3 MeV, or in a range of 1 MeV and 2 MeV. In someembodiments, further proton irradiations may be carried out such that anend-of-range peak of the protons is located within the chargecompensation structure, for example for precisely tuning thepunch-through-voltage, or correcting a charge compensation balance, orfor increasing avalanche robustness. The charge compensation structuremay be formed by super junction process technologies such as multipleepitaxy technology and deep trench technology. Also a combination ofmultiple epitaxy technology and deep trench technology may be used toformed the charge compensation device structure.

According to an embodiment of a semiconductor device, the semiconductordevice comprises a charge compensation structure including p-doped andn-doped regions arranged consecutively in a semiconductor substratealong a lateral direction. The semiconductor device further includes afirst dopant species dominating a doping profile of the p-doped regionsand a second dopant species dominating a doping profile of the n-dopedregions. The semiconductor device further includes hydrogen-relateddonors in the p-doped and n-doped regions, wherein an end-of-range peakof the protons is located within the charge compensation structure. Thehydrogen-related donors differ from the second dopant species. A maximumconcentration c_(max,n) of the hydrogen-related donors in the p-dopedregions of a first die of the plurality of semiconductor dies is morethan 5% greater, or more than 10% greater, or more than 30% greater, ormore than 50% greater than a maximum concentration c_(max,n) of thehydrogen-related donors in the p-doped regions of a second die of theplurality of semiconductor dies.

FIG. 7A is a schematic cross-sectional view of a semiconductor device701 comprising a charge compensation structure including n-doped andp-doped regions 711, 712 arranged consecutively in a semiconductorsubstrate 705 along a lateral direction x. The charge compensationstructure is based on multiple epitaxy technology in an upper part 751and is based on multiple epitaxy technology in a lower part 752. Inother words, the charge compensation structure illustrated in FIG. 7Aincludes multiple inter-diffused p-type sub-regions subsequentlyarranged along a vertical direction between opposite main surfaces ofthe semiconductor substrate. A first p-dopant species dominates a dopingprofile of the p-doped regions 712 and a second n-dopant speciesdominates a doping profile of the n-doped regions 711. The semiconductordevice 701 further includes hydrogen-related donors in the n-doped andp-doped regions 711, 712, wherein an end-of-range peak of the protons islocated within the charge compensation structure. Examples of dopingprofiles are illustrated next to the schematic cross-sectional view. Anexemplary doping profile along line E-E′ through one the p-doped regions712 is illustrated in the graph to the left of the cross-sectional viewillustrating concentration c versus depth, P₇ representing a dopingprofile of the first p-dopant species, whereas an exemplary dopingprofile along line F-F′ through one the n-doped regions 711 isillustrated in the graph to the right of the cross-sectional viewillustrating concentration c versus depth, N₇ representing a dopingprofile of the second n-dopant species, and N_(H1) representing a dopingprofile of the hydrogen-related donors in the n-doped and p-dopedregions 711, 712, wherein an end-of-range peak EP1 of the protons islocated within the charge compensation structure between the upper andlower parts 751, 752. Alternatively, the n-type interruption of thecompensation regions 711, 712 may be completely realized by theend-of-range of the proton-induced doping process. Alternatively, theend-of-range peak may be arranged within the lower part 752 of thecompensation structure.

Proton implantation into the semiconductor substrate 705 isschematically illustrated by dashed lines ending in an area of theend-of-range peak EP1. The semiconductor device 701 may further comprisea field stop zone 754 below the charge compensation structure.

FIG. 7B is a schematic cross-sectional view of a semiconductor device702 differing from the embodiment of FIG. 7A in that the upper part 751of the compensation structure is based on deep trench technology.

In the embodiments described above with respect to FIGS. 7A and 7B,multiple inter-diffused p-type sub-regions are subsequently arrangedalong a vertical direction between opposite main surfaces of thesemiconductor substrate. In some other embodiments, the upper and lowerparts 751, 752 of the compensation structure in an area of the p-dopedregions 712 is interrupted by an n-doped region 753 as is illustrated inthe schematic cross-sectional view of FIG. 7C. In the n-doped region, anend-of-range peak of the protons is located, and an doping ofhydrogen-related donors caused by proton irradiation and annealing and abackground n-doping is greater than any p-doping present in this region.

As is illustrated in the schematic cross-sectional views of FIGS. 7D andFIG. 7E, one or more further proton implantations may be carried outbased on ion implantation and annealing parameters determined by themeasured electric characteristic related to the charge compensationdevice, which may, in addition to or as an alternative to a Qoss(V)characteristic, include a breakdown voltage characteristic at one ormore positions across a surface of the semiconductor substrate. The oneor more further proton implantations may lead to a profile N_(H2)representing a doping profile of the hydrogen-related donors outside ofthe p-doped and n-doped regions 712, 711, wherein an end-of-range peakEP2 of the protons is located within the field stop zone 754. Accordingto an embodiment, at least one of number, dose and energy of protonirradiation are adjusted based on the measured value of the electriccharacteristic. According to an embodiment, the adjusted protonirradiation parameters for profile N_(H2) include an implantation dosein a range of 2×10¹⁴ cm⁻² and 8×10¹⁴ cm⁻² and an implantation energy ina range of 1.0 MeV and 3.0 MeV. According to an embodiment, the adjustedproton irradiation parameters for profile N_(H2) are configured to shifta charge balance of the charge compensation device structure based onthe measured value of the electric characteristic towards or to a targetcharge balance of the charge compensation device structure.

In some embodiments, by varying a thermal budget locally introduced intothe semiconductor substrate 705 by photon beam irradiation as describedin the embodiments above, for example with respect to FIG. 1F, acorrection of charge balance may be varied across a surface of thesemiconductor substrate 705 based on the measured electriccharacteristic.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

1-14. (canceled)
 15. A semiconductor wafer, comprising: a plurality of semiconductor dies, each of the plurality of semiconductor dies comprising a charge compensation structure including p-doped and n-doped regions arranged consecutively in a semiconductor substrate along a lateral direction; a first dopant species dominating a doping profile of the p-doped regions; a second dopant species dominating a doping profile of the n-doped regions; and hydrogen-related donors in the p-doped and n-doped regions, wherein the hydrogen-correlated donors differ from the second dopant species; and wherein a maximum concentration of the hydrogen-related donors in the p-doped regions of a first die of the plurality of semiconductor dies is more than 5% greater than a maximum concentration of the hydrogen-related donors in the p-doped regions of a second die of the plurality of semiconductor dies.
 16. The semiconductor wafer of claim 15, wherein each of the plurality of semiconductor dies comprises: an n-doped field stop zone between the charge compensation structure and a second side of the semiconductor substrate, and wherein, within a range of the n-doped field stop zone, an end-of-range peak profile of hydrogen-related donors is smaller than a profile of another n-type dopant species of the n-doped field stop zone.
 17. The semiconductor wafer of claim 15, wherein the hydrogen-related donors extend over at least 30% of a vertical extension of a drift zone between a first side and a second side of the semiconductor substrate.
 18. The semiconductor wafer of claim 15, wherein a concentration of the hydrogen-related donors is in a range of 1×10¹³ cm⁻³ and 5×10¹⁶ cm⁻³.
 19. The semiconductor wafer of claim 15, wherein the charge compensation structure includes upper and lower parts in an area of the p-doped regions, the upper and lower parts being interrupted by an n-doped intermediate region sandwiched between the upper and lower parts.
 20. The semiconductor wafer of claim 19, wherein a peak concentration of the hydrogen-related donors is located in the n-doped intermediate region. 